1. Field of the Invention
This invention relates to an optical device for use in display devices, light modulator devices, etc., and particularly to a novel optical device utilizing the swelling and shrinking of gel under thermal action.
2. Description of the Prior Art
Non-luminous display devices have been regarded as being important because they can produce natural color tone and will not cause any fatigue to human eyes, and they include, for example, electrochromic display devices (ECD), liquid crystal display devices (LCD), etc. However, their quality and performance are not satisfactory. For example, ECD is so low in display contrast that it is hardly observable in a dim place and discrimination of a fine image is difficult at a distance
On the other hand, LCD has such another disadvantage as a restricted angle of visual field, besides the said disadvantages.
There are the same problems as above even when they are used in the light modulator devices such as light shutters, etc.